debugfs_create_ulong — create a debugfs file that is used to read and write an unsigned long value.
|const char * name,|
|struct dentry * parent,|
|unsigned long * value|
const char * name
a pointer to a string containing the name of the file to create.
the permission that the file should have
struct dentry * parent
a pointer to the parent dentry for this file. This should be a
directory dentry if set. If this parameter is
NULL, then the
file will be created in the root of the debugfs filesystem.
unsigned long * value
a pointer to the variable that the file should read to and write from.
This function creates a file in debugfs with the given name that
contains the value of the variable
value. If the
mode variable is so
set, it can be read from, and written to.
This function will return a pointer to a dentry if it succeeds. This
pointer must be passed to the
debugfs_remove function when the file is
to be removed (no automatic cleanup happens if your module is unloaded,
you are responsible here.) If an error occurs,
NULL will be returned.
If debugfs is not enabled in the kernel, the value -
ENODEV will be
returned. It is not wise to check for this value, but rather, check for
NULL or !
NULL instead as to eliminate the need for #ifdef in the calling